Application Of Methyl Jasmonate Research Articles

Salicylic acid and jasmonic acid biosynthetic pathways are simultaneously activated in transgenic Arabidopsis expressing the rolB/C gene from Ipomoea batatas

The Agrobacterium rhizogenes root oncogenic locus (rol) genes interfere with hormone balance by altering their synthesis and/or recognition, giving rise to varied impacts on the physiological characteristics of plants and cell cultures. The homolog of the rolB and rolC genes from Ipomoea batatas, named Ib-rolB/C, similarly induces morphological and physiological alterations in transgenic Arabidopsis thaliana; however, its role in plant hormonal homeostasis has not been previously defined. In this study, we found that external application of salicylic acid (SA) and methyl jasmonate (MeJA) significantly upregulated Ib-rolB/C in detached I. batatas leaves. Furthermore, heterologous expression of Ib-rolB/C in A. thaliana markedly enhanced the accumulation of SA and MeJA, and to a lesser extent, elevated abscisic acid (ABA) levels, through the modulation of genes specific to hormone biosynthesis. Even though the RolB/RolC homolog protein has a notable structural resemblance to the RolB protein from A. rhizogenes, it exhibits a distinct localization pattern, predominantly residing in the cytoplasm and certain discrete subcellular structures, instead of the nucleus. Consequently, the functions of RolB/RolC in both naturally and artificially transgenic plants are linked to changes in the hormonal state of the cells, though the underlying signaling pathways remain to be elucidated.

RNA sequencing analysis reveals PgbHLH28 as the key regulator in response to methyl jasmonate-induced saponin accumulation in Platycodon grandiflorus

Abstract Platycodon grandiflorus (Jacq.) A. DC, known for its saponin content, can potentially prevent and treat cerebrovascular diseases and COVID-19. Triterpenoid saponin biosynthesis in plants is enhanced by methyl jasmonate (MeJA) application. However, the underlying molecular mechanisms of MeJA-induced saponin biosynthesis remain unknown in P. grandiflorus. In the current study, exogenous application of 100 μmol/l MeJA was identified to be optimal for promoting saponin accumulation. RNA sequencing analysis demonstrated the PgbHLH28 gene as a key regulatory factor responding to MeJA during saponin accumulation. Overexpression of PgbHLH28 in P. grandiflorus increased saponin content, while silencing of PgbHLH28 significantly inhibited saponin synthesis, suggesting that PgbHLH28 acts as a positive regulator of saponin biosynthesis. Yeast one-hybrid and dual luciferase assays demonstrated that PgbHLH28 directly bound to the promoters of PgHMGR2 and PgDXS2 to activate gene expression. PgHMGR2 and PgDXS2 transformation promoted saponin accumulation, while silencing of these genes inhibited saponin biosynthesis. This study determined that MeJA promoted saponin accumulation in P. grandiflorus by inducing PgbHLH28 gene expression and activating downstream genes (PgHMGR2 and PgDXS2) involved in saponin biosynthesis. In conclusion, a complex regulatory network governing saponin biosynthesis following MeJA treatment was elucidated, offering a theoretical foundation for enhancing saponin content and biosynthesis efficacy in P. grandiflorus.

Genome-Wide Identification and Analysis of APC E3 Ubiquitin Ligase Genes Family in Triticum aestivum.

E3 ubiquitin ligases play a pivotal role in ubiquitination, a crucial post-translational modification process. Anaphase-promoting complex (APC), a large cullin-RING E3 ubiquitin ligase, regulates the unidirectional progression of the cell cycle by ubiquitinating specific target proteins and triggering plant immune responses. Several E3 ubiquitin ligases have been identified owing to advancements in sequencing and annotation of the wheat genome. However, the types and functions of APC E3 ubiquitin ligases in wheat have not been reported. This study identified 14 members of the APC gene family in the wheat genome and divided them into three subgroups (CCS52B, CCS52A, and CDC20) to better understand their functions. Promoter sequence analysis revealed the presence of several cis-acting elements related to hormone and stress responses in the APC E3 ubiquitin ligases in wheat. All identified APC E3 ubiquitin ligase family members were highly expressed in the leaves, and the expression of most genes was induced by the application of methyl jasmonate (MeJA). In addition, the APC gene family in wheat may play a role in plant defense mechanisms. This study comprehensively analyzes APC genes in wheat, laying the groundwork for future research on the function of APC genes in response to viral infections and expanding our understanding of wheat immunity mechanisms.

Integrative metabolome and transcriptome analysis characterized methyl jasmonate-elicited flavonoid metabolites of Blumea balsamifera.

As a commonly used medicinal plant, the flavonoid metabolites of Blumea balsamifera and their association with genes are still elusive. In this study, the total flavonoid content (TFC), flavonoid metabolites and biosynthetic gene expression patterns of B. balsamifera after application of exogenous methyl jasmonate (MeJA) were scrutinized. The different concentrations of exogenous MeJA increased the TFC of B. balsamifera leaves after 48 h of exposure, and there was a positive correlation between TFC and the elicitor concentration. A total of 48 flavonoid metabolites, falling into 10 structural classes, were identified, among which flavones and flavanones were predominant. After screening candidate genes by transcriptome mining, the comprehensive analysis of gene expression level and TFC suggested that FLS and MYB may be key genes that regulate the TFC in B. balsamifera leaves under exogenous MeJA treatment. This study lays a foundation for elucidating flavonoids of B. balsamifera, and navigates the breeding of flavonoid-rich B. balsamifera varieties.

Natural resistance-associated macrophage proteins are involved in tolerance to heavy metal Cd2+ toxicity and resistance to bacterial wilt of peanut (Arachis hypogaea L.)

Peanut (Arachis hypogaea L.) is one of the most important oil and industrial crops. However, heavy-metal pollution and frequent soil diseases, poses a significant threat to the production of green and healthy peanuts. Herein, we investigated the effects of heavy metal Cd2+ toxicity to the peanuts, and screened out two peanut cultivars H108 and YZ 9102 with higher Cd2+-tolerance. RNA-seq revealed that Natural resistance-associated macrophage proteins (NRAMP)-like genes were involved in the Cd2+ stress tolerance in H108. Genome-wide identification revealed that 28, 13 and 9 Nramp-like genes existing in the A. hypogaea, A. duranensis and A. ipaensis, respectively. The 50 peanut NRAMP genes share conserved architectural characters, and they were classified into two groups. Expressions of AhNramps, particularly AhNramp4, AhNramp12, AhNramp19, and AhNramp25 could be greatly induced by not only cadmium toxicity, but also copper and zinc stresses. The expression profiles of AhNramp14, AhNramp16 and AhNramp25 showed significant differences in the H108 (resistance) and H107 (susceptible) under the infection of bacterial wilt. In addition, we found that the expression profiles of AhNramp14, AhNramp16, and AhNramp25 were greatly up- or down-regulated by the application of exogenous salicylic acid, methyl jasmonate, and abscisic acid. The AhNramp25, of which expression was affected by both heavy metal toxicity and bacterial wilt infection, were selected as strong candidate genes for peanut stress breeding. Our findings will provide an additional information required for further analysis of AhNramps involved in tolerance to heavy metal toxicity and resistance to bacterial wilt of peanut.

Pre- and Post-harvest Elicitation with Methyl Jasmonate and Salicylic Acid Followed by Cold Storage Synergistically Improves Red Colour Development and Health-Promoting Compounds in Blood Oranges

Red blush is one of the key quality markers of blood orange fruit (Citrus sinensis L. Osbeck). Therefore, the influence of pre- (1, 2, and 3 mM) and postharvest (0.5, 1, and 1.5 mM) methyl jasmonate (MeJA) and salicylic acid (SA) (1, 2, and 3 mM) treatments on redness, colouring pigments, and health-promoting compounds in cold stored ‘Tarocco Ippolito’ blood oranges was investigated. Preharvest application of 3 mM MeJA significantly increased rind citrus colour index (CCI) by 43.3% and colorimetric coordinate a* (redness) by 3.1% and decreased h° (hue angle, 0 = red), L* (lightness), and b* (yellowness) by 13.7%, 12.6%, and 23.4%, respectively. This treatment also enhanced CCI (57.4%), reduced h° (16.5%) and L* (36.4%), and increased total anthocyanins (88%), monomeric anthocyanins (117%), and flavonoids (77%) in the juice. Postharvest dip of 1.5 mM MeJA (5 min) improved CCI of juice (53.6%) and a* (5.5%), reduced h° (15.9%), L* (19.8%), and b* (19.4%), and increased total anthocyanins (66.7%), monomeric anthocyanins (74%), and flavonoids (23.4%) in the juice. Preharvest application of 1 mM SA increased rind CCI (50.8%) and reduced L* (13.6%), b* (16.4%), and h° (29.5%). All preharvest SA treatments significantly increased total phenolics in the juice. Lycopene was increased (61.7%) by 5 min postharvest dip of 3 mM SA. In conclusion, 3 mM preharvest spray application of MeJA four weeks before harvest and postharvest dip of 1.5 mM MeJA (5 min) are effective in improving red colour of rind and juice and health-promoting compounds in blood orange juice.

Physiological changes induced by hardening in seedlings of eucalyptus as a function of growth stages

Hardening appears as an interesting strategy to improve the quality of seedlings in forest nurseries, favoring their survival in the field. Thus, the objective of this research was to show the physiological alterations resulting from the application of methyl jasmonate and stem flexion in three stages of growth in Eucalyptus urograndis seedlings. The experiment was carried out in Marechal Cândido Rondon, Paraná, and Eucalyptus urograndis seedlings were used. Treatments consisted of weekly applications of methyl jasmonate (MeJA), daily imposition of stem flexion and a control treatment. Analyzes included quantification of flexural stiffness, lignin content in stems and roots, phenolic compounds in leaves and roots, electrolyte leakage in roots and field survival. In seedlings of Eucalyptus urograndis at 100 days after emergence (DAE) and at the three distances used to evaluate flexural rigidity, the highest averages were observed in seedlings submitted to chemical and mechanical treatments, coinciding with the increase in lignin content in the stem. In the roots, after quantifying the extravasation of electrolytes in Stage I, the means decreased with the application of treatments. In the field phase, there were no statistically significant differences between seedling survival assessments, quantified every 15 days, for a period of 90 days after planting. However, seedlings in Stage I were lost because they were too young and could not tolerate the stressful conditions observed in the field.

Berry secondary metabolites and leaf physiological parameters are independently regulated by exogenous methyl jasmonate application in Sangiovese grapevines (Vitis vinifera L.)

The role of jasmonates as elicitor of secondary metabolites is well known, and many experiments have been conducted in grapevine to evaluate their effects on berry and wine quality. Even though most of these studies used foliar jasmonates applications, little investigations have been done to assess the effects on leaves which, in turn, may indirectly affect grape metabolism potentially involving a long distance signaling or crosstalk. In this experiment we jointly investigated the specific effect of jasmonates on grape berry secondary metabolites and leaf physiological parameters to better comprehend their elicitation mechanisms in grapevine. A 10 mM methyl jasmonate (MeJA) solution was applied during the lag-phase only on the leaves or only on the clusters and compared to an untreated control. The MeJA specifically affected leaf physiological parameters and berry metabolism in the treated area. When applied only on the leaves, gas exchange parameters and leaf efficiency were reduced, stimulating the senescence mechanisms, without affecting berry metabolism. On the contrary, MeJA applied on the clusters significantly delayed berry ripening, leading to hypothesize a re-route of the berry carbon resources through the biosynthesis of volatile organic compounds which were strongly increased, especially the monoterpenes in their glycosylated form.

Cloning and functional characterization of a cinnamate 4-hydroxylase gene from the hornwort Anthoceros angustus

Hornworts, as the sister group to liverworts and mosses, comprise bryophytes, which are critical in understanding the evolution of key land plant traits. Cinnamate 4-hydroxylase (C4H) catalyzes the second step of the phenylpropanoid pathway to synthesize the precursor of numerous phenolic compounds, such as lignin and flavonoids. However, C4H in the hornwort Anthoceros angustus has not yet been cloned and functionally characterized. In this work, we screened the transcriptome database of A. angustus and identified one C4H gene, AnanC4H. AnanC4H maintained conserved cytochrome P450 domains with other typical plant C4Hs. Ultraviolet B irradiation and exogenous application of methyl jasmonate (MeJA) induced the expression of AnanC4H to varying degrees. The coding sequence of AnanC4H was expressed in yeast, and the recombinant proteins were isolated. The recombinant proteins of AnanC4H catalyzed the conversion of trans-cinnamic acid to p-coumaric acid and catalyzed the conversion of 3-hydroxycinnamic acid to caffeic acid. AnanC4H showed higher affinity for trans-cinnamic acid than for 3-hydroxycinnamic acid, but there was no significant difference in the catalytic efficiency of AnanC4H for the two substrates in vitro. Moreover, the expression of AnanC4H in Arabidopsis thaliana led to an increase in both the lignin content and the number of lignified cells in stems. However, there was no significant change in flavonoid content in transgenic Arabidopsis plants.

Metabolomics Reveals Rubiadin Accumulation and the Effects of Methyl Jasmonate Elicitation in Damnacanthus major Calli.

Callus suspension techniques have been considered attractive for improving bioactive metabolite productivity; methyl jasmonate (MeJA) is a widely used elicitor for stimulating synthetic pathways. In this study, a multivariate analysis-based metabolomics approach was employed to investigate the primary and specialized metabolites in the leaves, unelicited calli, and 100 or 200 μM MeJA elicited calli of Damnacanthus major. Rubiadin, a powerful anthraquinone with various therapeutic properties, was only identified in D. major calli, accumulating in a MeJA elicitation concentration-dependent manner. Callus cultures also contained high levels of amino acids, sugars, and phenolic compounds, indicating energy metabolism and metabolic adaptation responses for proliferation and stabilization. Regarding MeJA application, elicited calli contained higher amounts of quinic acid, kaempferol, and glucose with lower amounts of sucrose and raffinose than those in the unelicited control, which were closely related to protective mechanisms against MeJA. Moreover, excessive elicitation increased the asparagine, fructose, and raffinose levels and decreased the glucose and sucrose levels, which was ascribed to increased activation of the aminoacyl-tRNA biosynthesis pathway and wider utilization of glucose than of fructose after sucrose degradation. These results will be useful for optimizing plant cell culture techniques to achieve high production rates for valuable specialized metabolites.

MORPHOPHYSIOLOGICAL CHANGES IN SEEDLINGS OF Eugenia uniflora L. AFTER CHEMICAL HARDENING

Using quality seedlings increases the chances of survival and development after planting. Hardening aims to modify the morphology of seedlings to acclimatize them to stressful field conditions. The objective of this study was to quantify the effects of chemical hardening with methyl jasmonate on the morphophysiology of Eugenia uniflora L. seedlings subjected to 12 days of water deficit. Seedlings were hardened with doses of 0, 50, 100, and 150 μmol L-1 of methyl jasmonate (MeJA). Afterward, they were transplanted into pots with soil and subjected to water deficit for 12 days. During that period, we assessed shoot height (H), stem diameter (SD), leaf area (LA), leaf dry mass (LDM), stem dry mass (SDM), root dry mass (RDM), total dry mass (TDM), relative water content (RWC), robustness index (RI), Dickson quality index (DQI), shoot/root ratio (S/R), stomatal conductance (Sc) and evapotranspiration (ET). The experiment was conducted in a randomized block design with five blocks. Variables RI, DQI, LA, RWC, and TDM values presented a quadratic trend, with promising results from the 50 and 100 µmol L-1 doses. Sc and ET values were influenced by water deficit. Under conditions of water restriction, application of MeJA in adequate doses promoted morphophysiological changes and induced defense strategies in E. uniflora seedlings. Doses of methyl jasmonate between 50 and 100 µmol L-1 resulted in seedlings with greater tolerance to water deficit for 12 days.

FISIOLOGÍA DE LA MADURACIÓN Y MANEJO EN POSTCOSECHA DE FRUTILLA CHILENA (Fragaria chiloensis)

The Chilean strawberry (Fragaria chiloensis) is a native species to Chile. Consumers value this fruit for its organoleptic properties, but it is highly perishable. Since it is a non-climacteric fruit, harvesting at the optimum ripening stage is essential to ensure its quality during commercialization. In this fruit, quality is determined by appearance, flavor, aroma, nutritional value, and firmness, which changes during ripening. The species presents a high rate of firmness loss or softening, associated with the elevated enzymatic activity of cell wall-modifying enzymes of the pectin and hemicellulose fractions, such as polygalacturonase, α-arabinofuranosidase, β-galactosidase, endo-glucanase, β-xylosidase, xyloglucan endotransglycosilase/hydrolase and rhamnogalacturonan lyase at different ripening stages. Firmness is a key trait for commercialization and organoleptic quality; hence, its management during storage is necessary. Different studies have investigated the effects of pre or postharvest treatments, such as modified atmosphere packaging and exogenous applications of calcium, auxin, methyl jasmonate, chitosan, and hydrogen sulfide, which maintain fruit firmness by reducing pectin solubilization and improve other attributes responsible for organoleptic and nutritional quality during storage. This literature review focuses on the ripening biology of Fragaria chiloensis and recent findings regarding softening and its biochemical and molecular basis, as well as interventions oriented to maintain the quality and extend the shelf-life of this fruit.

Lipoxygenases regulate digestive enzyme inhibitor activities in developing seeds of field-grown soybean against the southern green stink bug (Nezara viridula).

Soybean (Glycine max ) is the world's most widely grown seed legume. One of the most important pests that decrease seed quality and reduce yield of soybean crops is the southern green stink bug (Nezara viridula ). Insect damage triggers accumulation of defensive compounds such as protease inhibitors (PIs), isoflavonoids and reactive oxygen species, which are regulated by the lipoxygenase (LOX)-regulated jasmonic acid (JA) to stop insect feeding. This study identified and characterised the role of LOX isoforms in the modulation of chemical defences in seeds of field-grown soybean that decreased digestive enzyme activities of N. viridula after insect attack. Stink bugs attack increased LOX 1 and LOX 2 expression, and activities of LOX 1 and LOX 3 isoenzymes in developing soybean seeds. In addition, stink bug damage and methyl jasmonate application induced expression and activity of both cysteine PIs and trypsin PIs in developing soybean seeds, suggesting that herbivory induced JA in soybean seeds. High PI activity levels in attacked seeds decreased cysteine proteases and α-amylases activities in the gut of stink bugs that fed on field-grown soybean. We demonstrated that LOX isoforms of seeds are concomitantly induced with JA-regulated PIs by stink bugs attack, and these PIs inhibit the activity of insect digestive enzymes. To our knowledge, this is the first study to investigate the participation of LOX in modulating JA-regulated defences against stink bugs in seeds of field-grown soybean, and our results suggest that soybean PIs may inhibit α-amylase activity in the gut of N. viridula .

Foliar application of methyl jasmonate and methyl jasmonate + urea: effect on nitrogen compounds in Tempranillo grapes over two vintages

The effects of foliar application of methyl jasmonate and methyl jasmonate plus urea on the amino acids content of Tempranillo grapes were evaluated during two seasons (2019 and 2020). In 2019, the foliar treatments favored an increase in ammonium nitrogen (N), amino N and yeast assimilable N when compared to the control grapes; whereas, in 2020, treatments did not affect N parameters in grapes. In 2019, foliar application of both treatments was effective in improving amino acids content in grapes, being significantly higher the effect of methyl jasmonate plus urea treatment than methyl jasmonate treatment. However, in 2020, the effect of both treatments on amino acid content was minor. The different effect among seasons could be explained by environmental conditions and by the differences in N content in grapevines. A multifactorial analysis and discriminant study were carried out, showing that both treatments enhanced amino acid content in grapes. The effect of methyl jasmonate plus urea was stronger than the effect of methyl jasmonate treatment. Also, a great effect of season on amino acids composition was observed.

Postharvest application of methyl jasmonate alleviates lignin accumulation in stone cells of pear fruit during low-temperature storage

Pear fruits are usually harvested in the mid-summer and need to be stored at low temperatures to prevent deterioration and extend their shelf-life. However, low temperature induces lignin deposition and increases stone cell numbers, impairing fruit quality and decreasing consumer satisfaction. In this study, we found that postharvest application of MeJA could efficiently inhibit lignification in pear fruit 'Xinli No.7′ and 'Zaosu' under low-temperature storage (4 °C). Transcriptomic and metabolomic analyses indicated that MeJA application may inhibit lignin polymerization and aggregation by repressing the expression of genes encoding enzymes in the late stage of the lignin biosynthesis pathway. Also, MeJA may alleviate ROS-mediated lignification by promoting flavonoids accumulation. Moreover, the inhibition of the lignification process by MeJA likely depends on the activation of endogenous JA biosynthesis and its signaling pathway. Our findings shed light on the lignification process and the role of MeJA in its regulation in pear fruit under low-temperature storage, and provide a means of alleviating deleterious lignification during storage.

Different Effects and Application of Methyl Jasmonate on Triticum aestivum L. by aphid Attack

Wheat (Triticum aestivum L.) widely grown in Pakistan during winter season. Aphid is one of the biological factors that inhibits seed germination and plant development. Methyl jasmonate is a plant growth regulator known to take part in defense responses against different types of stresses including Aphid attack. The current study was conducted to improve the growth of the wheat by the foliar application of Methyl jasmonate. Two wheat varieties (Shafaq and Gold) were be sown in plastic pots filled with 6 kg soil in each pot. After germination, wheat plants were treated with different Aphids. After three weeks of treatment data about survival percentage, root attributes, shoot attributes and nutrient analysis was be recorded using standard procedure. The experiment was be conducted under a complete randomized design (CRD) with three replicates and results was be deducted after statistical analysis. Different concentrations of methyl jasmonate (100 micromolar and 1mM) were applied to 20 days old wheat plant. Rhopalosiphum padi was allowed to infest the methyl jasmonate treated plants as well as non-treated plants. Control plants were covered with net and no concentration of methyl jasmonate were applied. Aphids were allowed to infest the plant for 48 hours, after that the plant from all treatments were sampled for all physiological studies. Methyl jasmonate treated plants as well as control plants were used for direct aphid population count after every week. Concluded results depicted that plants exposed to different concentrations of methyl jasmonate affected the root and shoot length, plant height which was further improved through MeJA supplementation.

Preharvest application of MeJA enhancing the quality of postharvest grape berries via regulating terpenes biosynthesis and phenylpropanoid metabolisms

Methyl jasmonate (MeJA) is an important phytohormone that regulates the development of grape, but the effect and underpin mechanism of its preharvest application on secondary metabolites accumulation in postharvest grape berries are still unclear. In this study, the transcriptome profiles combined with metabolic components analysis were used to determine the effect of preharvest MeJA application on the quality formation of postharvest rose-flavor table grape Shine Muscat. The results indicated that preharvest MeJA treatment had no significant effect on TSS content, but had a down-regulation effect on the accumulation of reducing sugar and titratable acid in the berries. The content of chlorophylls and carotenoids in treated berries was significantly higher than that of the control. Many phenolic components, such as trans-ferulic acid, resveratrol, quercetin, and kaempferol, were sensitive to MeJA and their contents were also significantly higher than that of the control under MeJA treatments during the shelf life. Compared with other volatile aroma components, terpenoid components were more sensitive to preharvest MeJA signals, the content of which presented an overall upward trend with increasing MeJA concentration and prolonging storage time. Furthermore, most of the differentially expressed genes in the general phenylpropanoid pathway and terpenoid biosynthesis pathway were up-regulated responding to MeJA signals. The most upregulated regulatory factors, such as VvWRKY72, VvMYB24, and VvWRI1, may be involved in MeJA signal transduction and regulation. Preharvest MeJA may be an effective technique for enhancing the quality of postharvest Shine Muscat grape berries, with its positive effect on enhancing the characteristic aroma and nutritional components.

Potential application of methyl jasmonate and γ-aminobutyric acid to preserve fruit quality and alleviate postharvest chilling in Orlando tangelo

Potential application of methyl jasmonate and γ-aminobutyric acid to preserve fruit quality and alleviate postharvest chilling in Orlando tangelo

Kiwifruit Resistance to Sclerotinia sclerotiorum and Pseudomonas syringae pv. actinidiae and Defence Induction by Acibenzolar-S-methyl and Methyl Jasmonate Are Cultivar Dependent.

Pathogen susceptibility and defence gene inducibility were compared between the Actinidia arguta cultivar 'Hortgem Tahi' and the two cultivars of A. chinensis 'Hayward' and 'Zesy002'. Plants were treated with acibenzolar-s-methyl (ASM) or methyl jasmonate (MeJA) one week before inoculation with Pseudomonas syringae pv. actinidiae (Psa biovar3) or Sclerotinia sclerotiorum, or secondary induction with chitosan+glucan (Ch-Glu) as a potential pathogen proxy. Defence expression was evaluated by measuring the expression of 18 putative defence genes. 'Hortgem Tahi' was highly susceptible to sclerotinia and very resistant to Psa, whereas 'Zesy002' was highly resistant to both, and 'Hayward' was moderately susceptible to both. Gene expression in 'Hayward' and 'Zesy002' was alike but differed significantly from 'Hortgem Tahi' which had higher basal levels of PR1-i, PR5-i, JIH1, NPR3 and WRKY70 but lower expression of RD22 and PR2-i. Treatment with ASM caused upregulation of NIMIN2, PR1-i, WRKY70, DMR6 and PR5-i in all cultivars and induced resistance to Psa in 'Zesy002' and 'Hayward' but decreased resistance to sclerotinia in 'Zesy002'. MeJA application caused upregulation of LOX2 and downregulation of NIMIN2, DMR6 and PR2-i but did not affect disease susceptibility. The Ch-Glu inducer induced PR-gene families in each cultivar, highlighting its possible effectiveness as an alternative to actual pathogen inoculation. The significance of variations in fundamental and inducible gene expression among the cultivars is explored.

Promoting resilience in ginger: Elicitor‐driven strategies to combat the rhizome rot disease

AbstractGinger rhizome rot is one of the most important diseases brought about by the interaction of various pathogens. The present study revealed the association of Pythium aphanidermatum, Fusarium oxysporum, Fusarium solani, Sclerotium rolfsii, Ralstonia solanacearum and Meloidogyne hapla causing the rhizome rot of ginger. The use of specific primers revealed the species‐level identification of the pathogen and Koch postulates proved the pathogenicity of individual pathogen. Till date, there are no resistant varieties available and the available management strategies are cumbersome because of the complex nature of pathogens involved. In the present study, we evaluated the effect of different elicitors to induce resistance against complex pathogens. External application of elicitors resulted in higher expression of defence response genes such as the ethylene responsive transcription factor, HMGR, HMGS, HSP, ABC, MLO, WRKY, callose synthase, glucanase and PR‐5. All the genes were expressed in higher folds as compared to zero hours during the real‐time PCR analysis. External application of methyl jasmonate as prophylactic manner resulted in reduced per cent disease incidence and rhizome rot as compared to curative treatments.